U.S. patent number 5,199,913 [Application Number 07/884,763] was granted by the patent office on 1993-04-06 for small, jet-propelled boat.
This patent grant is currently assigned to Sanshin Kogyo Kabushiki Kaisha. Invention is credited to Hiroshi Tasaki, Makoto Toyohara.
United States Patent |
5,199,913 |
Toyohara , et al. |
April 6, 1993 |
Small, jet-propelled boat
Abstract
A jet-propelled craft includes a hull, an engine installed
within the hull, a duct positioned in the stern area of said hull,
and an impeller which is turned by the rotational force of the
engine to create a jet stream within the duct. The craft also
includes left and right secondary water-intake openings on the
bottom of the hull which are positioned a specific distance apart
on the left and right in the hull, the duct including branches
connected to the left and right secondary water-intake openings. By
equipping the secondary water-intake openings with a valve which
closes when a sharp turn is made in the above mentioned boat and
the valve is on the outside with respect to the direction of the
turn, air is prevented from entering the outside secondary duct and
a loss of propulsive force is prevented.
Inventors: |
Toyohara; Makoto (Hamamatsu,
JP), Tasaki; Hiroshi (Hamamatsu, JP) |
Assignee: |
Sanshin Kogyo Kabushiki Kaisha
(JP)
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Family
ID: |
15285032 |
Appl.
No.: |
07/884,763 |
Filed: |
May 18, 1992 |
Foreign Application Priority Data
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May 16, 1991 [JP] |
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3-141137 |
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Current U.S.
Class: |
440/47; 114/55.5;
440/38 |
Current CPC
Class: |
B63H
11/103 (20130101) |
Current International
Class: |
B63H
11/103 (20060101); B63H 11/00 (20060101); B63H
011/103 () |
Field of
Search: |
;440/38-43,46,47
;114/270 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1-145598 |
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Mar 1988 |
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JP |
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127187 |
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May 1990 |
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JP |
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Primary Examiner: Sotelo; Jesus D.
Attorney, Agent or Firm: Bacon & Thomas
Claims
We claim:
1. A jet-propelled boat including a hull, a bottom side of which is
under water when operating the boat, a main duct positioned in the
hull, impeller means within the main duct for creating a jet stream
within the main duct, and first and second water-intake openings on
the bottom of the hull positioned a predetermined distance apart on
opposite sides of the hull and connected by respective duct
branches to the main duct;
means including valves positioned to selectively open and close
each of the first and second water-intake openings; and
means for controlling said valves to close one of said first and
second openings when a turn is made in said boat such that said one
of said openings which is positioned on the outside of said boat
with respect to a direction of the turn is always closed to thereby
prevent air from entering said one of said openings when it is
exposed to the air during the turn so that only the opening which
is positioned on the inside of said boat with respect to the
direction of the turn will be open.
2. A boat as claimed in claim 1, wherein said main duct includes a
main intake opening positioned at a center of the bottom of the
hull such that said main intake opening is always open and always
under water during operation of said boat.
3. A boat as claimed in claim 1, wherein said means for controlling
said valves includes means for detecting a deviation of said boat
from a vertical position during the turn and for controlling said
valves such that said one of said first and second openings remains
closed in response to detection that the deviation exceeds a
predetermined angle.
4. A boat as claimed in claim 3, wherein said means for controlling
said valves includes a gyroscopic sensor.
5. A boat as claimed in claim 3, wherein said means for controlling
said valves further comprises means including a throttle position
sensor for detecting whether an engine throttle has been opened
beyond a predetermined position and for preventing opening of said
valves unless said throttle has been opened beyond the
predetermined position.
6. A boat as claimed in claim 1, wherein said means for controlling
said valves further comprises means including a throttle position
sensor for detecting whether an engine throttle has been opened
beyond a predetermined position and for preventing opening of said
valves unless said throttle has been opened beyond the
predetermined position.
7. A boat as claimed in claim 1, wherein said valves are sliding
valves.
8. A boat as claimed in claim 1, wherein said means for controlling
said valves includes DC motors arranged to selectively move said
valves to close one of said first and second openings.
9. A jet-propelled boat including a hull, a bottom side of which is
under water when operating the boat, a main duct including a main
intake opening positioned at a center of the bottom of the hull
such that said main intake opening is always under water during
operation of said boat, impeller means within the main duct for
creating a jet stream within the main duct, and a secondary
water-intake opening on the bottom of the hull positioned a
predetermined distance from the main intake opening and connected
by a duct branch to the main duct;
valve means including a valve positioned to selectively open and
close said secondary water-intake opening; and
valve control means for controlling said valve to close said
secondary water-intake opening when said secondary water-intake
opening is positioned on an outside of said boat with respect to a
turning direction to thereby prevent air from entering said
secondary intake opening when it is exposed to the air during a
turn.
10. A boat as claimed in claim 9, wherein said valve control means
includes means for detecting a deviation of said boat from a
vertical position and for controlling said valve to close said
secondary water-intake opening in response to detection that the
deviation exceeds a predetermined angle.
11. A boat as claimed in claim 10, wherein said valve control means
includes a gyroscopic sensor.
12. A boat as claimed in claim 10, wherein said valve control means
further comprises means including a throttle position sensor for
detecting whether an engine throttle has been opened beyond a
predetermined position and for preventing opening of said valve
unless said throttle has been opened beyond the predetermined
position.
13. A boat as claimed in claim 9, wherein said valve control means
further comprises means including a throttle position sensor for
detecting whether an engine throttle has been opened beyond a
predetermined position and for preventing opening of said valve
unless said throttle has been opening beyond the predetermined
position.
14. A boat as claimed in claim 9, wherein said valve is a sliding
valve.
15. A boat as claimed in claim 14, wherein said valve control means
includes a DC motor arranged to selectively move said valve to
close said secondary water-intake opening.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention concerns a small, jet-propelled boat. In particular,
it concerns a small, jet-propelled boat in which lowered propulsive
force during sharp turns can be prevented.
2. Description of Related Art
In the past, when making sharp turns in a small, jet-propelled
boat, the operator of the boat would lean his body weight toward
the inside of the turn. When this was done in the usual type of
small, jet-propelled water craft having just one water intake
opening located in the bottom center of the hull, the water intake
opening tended to rise above the surface of the water with just a
small part of it remaining submerged. The result was that a large
volume of air would be taken in, impeding water intake and causing
a dramatic drop in propulsion. To prevent this type of lowered
propulsion, it was proposed (see, for example, Japan Utility Patent
Application Publication Hei 1-145598) to provide two water intake
openings which were separate and independent of each other and
which were positioned left and right on the hull a specific
distance apart. However, the proposed solutions in Japan Utility
Patent Application Publication Hei 1-145598 and their prior art
examples did not sufficiently attain their objective of preventing
the drop in propulsion.
Because both of the water intakes and the duct were always open
during turns, and although no air would be taken in at the intake
opening on the inside of the turn, the intake on the outside would
bring in a large amount of air because it was positioned above the
surface of the water, resulting in decreased propulsion.
A principal objective of this invention is to reduce the amount of
air intake during turns to an absolute minimum and to thereby
prevent the resultant drop in propulsion.
SUMMARY OF THE INVENTION
In order to achieve the above-specified objective, the invention
provides a small, jet-propelled boat which includes a hull and an
engine installed within the hull, a duct positioned in the stern
area of the hull, an impeller which is turned by the rotational
force of the engine and which creates a jet stream within the duct,
and left and right secondary water-intake openings on the bottom of
the hull which are positioned a specific distance apart on the left
and right in the hull. The duct branches left and right on the
upstream side and connects to the left and right secondary
water-intake openings, which are equipped with a valve to open and
close them so that when a sharp turn is made in the boat, the
outside duct valve, with respect to the direction of the turn, is
closed.
The invention therefore establishes secondary water-intakes on the
left and right sides of the hull and also provides valves for the
opening and closing of those intakes. When a sharp turn is made,
the valve on the outside secondary water-intake is closed so that
it can take in no water. Accordingly, this also prevents air from
being drawn in from the part of the secondary water-intake which is
positioned above the surface. Since the valve on the inside side of
the turn remains opened and since that secondary water-intake
remains deeply submerged below the water surface, only water, and
no air is taken in through that secondary water-intake.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a partial cross-sectional side view of a pump unit for
use in a small, jet propelled boat constructed in accordance with
the principles of a preferred embodiment of the invention.
FIG. 2 is a bottom view of the preferred small, jet-propelled boat
shown while making a left turn.
FIG. 3 is a bottom view of the preferred small, jet-propelled boat,
shown while proceeding straight ahead.
FIG. 4 is a cross-sectional side view taken along line IV--IV of
FIG. 2.
FIG. 5 is a cross-sectional side view taken along line V--V of FIG.
3.
FIG. 6 is a block diagram of a valve control device for controlling
opening and closing of the sliding valves.
FIG. 7 is a flow chart showing the drive control for the sliding
valve.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIGS. 1 through 7 show an embodiment of a small, jet-propelled boat
constructed in accordance with the principles of a preferred
embodiment of the invention.
Referring to FIGS. 1, 3 and 5, the preferred jet-propelled boat
includes a hull 10, a bottom 12, a steering wheel 14, a pump unit
20, and a nozzle 27 which pivots on pivot shaft 32 according to
whether steering wheel 14 is set straight-ahead or to the side.
The pump unit 20 is attached to the stern area of the hull 10. Pump
unit 20 creates propulsion to drive the boat 10 by means of an
engine (not shown) which drives the pump in known fashion by
causing the pump to forcefully expel water in response to rotation
of an impeller, 26.
At the center of the bottom of boat 12, in the left-right direction
of the hull 10 as shown in FIGS. 2 and 3, is the main water intake
21 which is a roughly rectangular opening following the contours of
the bottom of the boat 12. This main water intake opening 21
connects to main duct 23, which initially slopes upward, then stays
horizontal as it extends toward the stern where it connects to
nozzle 27, best shown in FIG. 1. Inside the horizontal part of the
main duct 23 is a drive shaft 25. Drive shaft 25 is connected at
the front to the engine (not shown) mounted on the hull 10, and at
the rear, to impeller 26. The rotation of the engine rotates
impeller 26 creating a jet stream within main duct 23.
On the left and right sides of the main water intake opening 21 in
the hull 12 are secondary water-intakes 22a and 22b which are
positioned a small interval away from main intake 21. Secondary
intakes 22a and 22b are rectangular, with the long sides of the
rectangle being parallel to the direction of propulsion. These
secondary water-intake openings 22a and 22b are connected,
respectively, to secondary ducts 24a and 24b. As shown in FIG. 5,
secondary ducts 24a and 24b extend in close proximity to the main
duct as they extend upward, and as shown in FIG. 1, they slope
upward as they extend along the main duct toward the rear.
Secondary ducts 24a and 24b are joined to the main duct 23 in the
area where the main duct runs horizontally, opening into flow
mixing openings 28a and 28b where the flow of the secondary ducts
24a and 24b is combined with that of the main duct 23.
Water intake screen 29 is attached to the main water intake. This
water intake-screen has a plurality of rectangular openings with
the long sides of the rectangles being parallel to the direction of
propulsion. The function of the water-intake screen 29 is to
prevent the entry of foreign materials into the main duct 23.
Secondary water-intakes 22a and 22b are equipped, respectively,
with slide valves 30a and 30b and valve grooves 31a and 31b in
which the valves are free to slide forward and backward. When these
slide valves 30a and 30b are moved forward (the condition shown by
the solid lines in FIG. 1), the secondary water-intake openings 22a
and 22b are free. As will be described below, this allows water to
be drawn into the secondary ducts 24a and 24b. Conversely, when
slide valves 30a and 30b are moved to the rear, the secondary
water-intake openings 22a and 22b are closed, preventing entry of
water into secondary ducts 24a, 24b.
Connecting rods 33a and 33b are attached to slide valves 30a and
30b, respectively. Connecting rods 33a and 33b are also connected
to DC motors 40a and 40b. These connections allow the DC motors 40a
and 40b, through their respective connecting rods 33a and 33b, to
operate the slide valves 30a and 30b fore and aft, thereby opening
and closing secondary water-intake openings 22a and 22b, in
response to valve drive controller 47.
As shown in FIG. 1, a gyro sensor 45 is provided for detecting the
left-right tilt of the boat 10, and a throttle sensor 46 for
detecting the opening of an engine throttle valve (not shown).
Valve drive controller 47 drives DC motors 40a and 40b. As shown in
FIG. 6, the throttle sensor 46 and gyro sensor 45 are connected to
valve drive controller 47, and valve drive controller 47 separately
controls DC motors 40a and 40b as will be described in more detail
below.
Straight-ahead propulsion will now be described with reference to
FIGS. 1, 3 and 5. In response to actuation of a throttle (not
shown), the throttle valve is opened and the engine rotates. This
rotational force is transmitted by the drive shaft 25 to impeller
26, causing it to turn. The rotation of the impeller 26 creates a
jet stream within the main duct 23. Water is drawn in through the
main water intake opening 21, traverse the main duct 23, and is
expelled rearward as a jet flow from nozzle 27, the force of which
propels the boat 10 forward. At this time, as shown by the broken,
imaginary lines in FIG. 1, secondary water-intake openings 22a and
22b are open by slide valves 30a and 30b and there is no water
entering secondary ducts 24a and 24b. To wit, when the preferred
boat is propelled straight ahead, there is no water intake from the
secondary water-intake openings 22a and 22b, and the water only
enters through the main water intake opening 21.
Operation during turning will now be explained with reference to
FIGS. 1, 2 and 4. In the case where the steering wheel 14 is turned
to the left to make a slow and/or wide turn, the nozzle 27 is
directed so that the jet stream points to the left, causing the
boat 10 to turn left while the operator keeps the boat in a
vertical position. In this case, because the boat 10 has not
tilted, the gyroscopic sensor 45 allows slide valves 30a and 30b to
remain in the closed position. In this position, the only water
intake that occurs is from the main water intake 21.
When making a sharp and/or fast turn to the left by operating the
steering wheel 14, the body weight of the operator shifts to the
port side, in other words, the operator leans to the inside of the
turn. When this happens, the boat 10 tilts toward the port side
such as shown by the solid line in FIG. 4, and this causes the
secondary water-intake opening 22a on the port side, which is the
inside side of the turn, to be deeply immersed in the water. On the
other hand, on the starboard side, which is the outside side of the
turn, secondary water-intake opening 22b rises above the surface of
the water. The gyro sensor 45 detects the angle of tilt toward the
left and as a result, transmits a signal to the drive controller
47. In addition, throttle sensor 46 detects the degree to which the
throttle valve (not shown) is open, and those results are also
transmitted to the valve drive controller 47. If the degree of
opening of the throttle valve is above a certain angle (.theta. for
example) and if the tilt angle of the boat is above a certain angle
(.alpha. for example), then drive motor 40a on the port side (the
side toward which the boat is tilting) is activated, and the slide
valve on the port side 30a is opened. At this time, the starboard
slide valve 30b remains in the closed position. The result of this
is that secondary duct 24a on the port side is opened to water from
the secondary water-intake opening 22a and water is taken in. The
main water intake opening 21 remains open at all times, so water
intake is accomplished by both secondary water-intake opening 22a
and main water intake opening 21. However, on the starboard side,
i.e., the side on the outside of the turn, secondary water-intake
opening 22b remains closed so that no water can enter, the
secondary water-intake opening 22b being positioned above the
water's surface at this time. This avoids the problem of air being
drawn into the impleller 26. This prevention of the invasion of air
strongly reduces drops in propulsive force.
In the case where a right turn is made, the steering wheel 14 is
turned toward the right and the body weight of the operator is
shifted to the starboard side, i.e., toward the inside of the turn.
When this happens, the hull of the boat 10 tilts toward the
starboard side and the starboard side secondary water-intake
opening 22b on the inside of the turn becomes deeply submerged
below the water's surface. On the other hand, the port side
secondary water-intake opening 22a on the outside of the turn is
raised above the surface of the water. Gyro sensor 45 detects the
tilt toward the right and transmit that information to the valve
drive control device 47. The throttle valve opening is also
detected by sensor 46 at this time. If the throttle valve opening
is above a certain level, and if the tilt of boat 10 is beyond a
certain angle, controller 47 causes the DC motor 40b on the
starboard side to be activated to open the starboard side sliding
valve 30b. At this time, the port side sliding valve 30a REMAINS
closed.
The result is that starboard side secondary water-intake opening
22b, on the inside of the turn, takes in water through secondary
duct 24b. Meanwhile, the main water intake 21 always remains open,
but the port side secondary water-intake opening 22a, i.e., the
opening on the outside of the turn, REMAINS closed and does not
take in any water. Since the water is taken in only from the deeply
submerged inside secondary water-intake opening 22b and the main
intake opening 21, which is below the water's surface, it is
difficult for air to be introduced into the impeller 26. This works
to strongly inhibit any drop in propulsion which might be caused by
such air introduction.
Next, when the sharp turn has been completed and the boat begins to
move straight ahead, the operator shifts his weight toward the
center as he returns the steering wheel 14 to the straight-ahead
position. When this happens, the boat 10 returns to an upright
position from a tilted position and nozzle 27 is directed for
motion straight ahead. At this time, the gyro sensor 45 detects the
tilt angle of the boat 10, and the valve drive control device 47
drives either DC motor 40a or 40b in order to close the outside
sliding valve 30a or 30b. As a result, both the left and right
sliding valves 30a and 30b are in a closed condition (see FIG. 5)
and water intake takes place only through the main water intake
opening 21.
When the throttle valve opening is below a certain level as
detected by sensor 46, in other words, when the craft is operated
at a low speed, even if the gyro sensor 45 detects that the boat 10
is tilted beyond a certain angle, the valve drive control device 47
will not open either of the secondary water-intake valves.
Having thus described a specific preferred embodiment of the
invention, it will nevertheless be appreciated that numerous
variations will undoubtedly occur to those skilled in the art. For
example, in the above-described exemplary preferred embodiment, the
main water intake opening and the secondary water-intake openings
were established separately. However, there does not necessarily
have to be a main water intake opening at all. In such a case, both
of the sliding valves would be open when the craft is running
straight and, during sharp turns, only the sliding valve on the
outside of the turn would be closed. Also, in the preferred
embodiment, sliding valves are used, but it is also possible to use
other valve types, such as rotating valves. Moreover, the preferred
valves are mounted at the secondary water-intake openings so as to
prevent the taking in of water, but it would also be possible to
locate them a short distance away from these openings. Finally, the
above described preferred embodiment uses just one secondary
water-intake opening each on the left and right sides of the hull,
but it would of course be possible to use more than one on each
side, or to use none on one side. Accordingly, it is to be
understood that the invention is to be interpreted solely as set
forth in the appended claims, and is not to be limited by the above
description.
* * * * *